Drug interactions
Disopyramide + Efavirenz
Severity: Major
Disopyramide and Efavirenz: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs can prolong the QT interval, so together they raise the risk of torsades de pointes. Efavirenz may also lower disopyramide levels via CYP3A4 induction.
What this interaction means in plain words
Disopyramide and Efavirenz can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Disopyramide belongs to Cardiovascular; Efavirenz belongs to Anti Virals.
Why it happens
Additive QTc prolongation, plus efavirenz induction of CYP3A4 metabolism of disopyramide.
What to do
Avoid if possible and use an alternative antiarrhythmic or antiretroviral. If used together, obtain ECG monitoring, correct electrolytes and monitor disopyramide effect.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Other interactions of Disopyramide
- Amisulpride + Disopyramide Contraindicated
- Desipramine + Disopyramide Contraindicated
- Disopyramide + Dronedarone Contraindicated
- Disopyramide + Itraconazole Contraindicated
- Disopyramide + Ketoconazole Contraindicated
- Disopyramide + Maprotiline Contraindicated
Frequently asked questions
Can I take Disopyramide with Efavirenz?
MediHelp rates the interaction as major. Disopyramide and Efavirenz can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval, so together they raise the risk of torsades de pointes. Efavirenz may also lower disopyramide levels via CYP3A4 induction.
How serious is the interaction between Disopyramide and Efavirenz?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible and use an alternative antiarrhythmic or antiretroviral. If used together, obtain ECG monitoring, correct electrolytes and monitor disopyramide effect.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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